Surgical staplers are used to simultaneously make a longitudinal incision in tissue and apply lines of staples on opposing sides of the incision. Such instruments commonly include an end effector having a pair of cooperating jaw members that, if the instrument is intended for endoscopic or laparoscopic applications, are capable of passing through a cannula passageway. One of the jaw members receives a staple cartridge having at least two laterally spaced rows of staples—one on each side of the knife channel. The other jaw member defines an anvil having staple-forming pockets aligned with the rows of staples in the cartridge. The instrument includes a plurality of reciprocating wedges that, when driven distally, pass through openings in the staple cartridge and engage drivers supporting the staples to effect the firing of the staples toward the anvil. Simultaneously, a cutting instrument (or knife) is drawn distally along the jaw member so that the clamped tissue is cut and fastened (e.g., stapled) at the same time.
An example of a surgical stapler suitable for endoscopic applications is described in published U.S. patent application Pub. No. 2004/0232196 A1, entitled, “Surgical stapling instrument having separate distinct closing and firing systems,” the disclosure of which is herein incorporated by reference in its entirety. In use, a clinician is able to close the jaw members of the stapler upon tissue to position the tissue prior to firing. Once the clinician has determined that the jaw members are properly gripping tissue, the clinician can then fire the surgical stapler, thereby severing and stapling the tissue. The simultaneous severing and stapling actions avoid complications that may arise when performing such actions sequentially with different surgical tools that respectively only sever or staple.
Motor-driven endocutters are known in the art. In such devices, an electric motor powers the cutting and fastening action of the instrument. It is also known to use an on-board battery, located in the handle of the instrument, to power the motor. Published U.S. patent application Pub. No. 2007/0175952 A1, entitled “Motor-driven surgical cutting and fastening instrument with loading force feedback,” the disclosure of which is herein incorporated by reference in its entirety, describes one such motor-driven surgical instrument.
In motor-driven surgical instruments, it is sometimes preferable that the control circuit for controlling the operation of the motor does not include any integrated circuits (ICs) made of semiconductor material because it is often difficult, complicated, and expensive to sterilize a surgical instrument including ICs.